A. V. Dvurechenskii, A. P. Kovchavsev, G. L. Kuryshev, I. A. Ryazantsev, A. I. Nikiforov, O. P. Pchelyakov
Institute of Semiconductor Physics, Siberian Branch RAS, Novosibirsk, Russia
Si junction (of p-i-n-diode type) containing Ge of self-assembled quantum dots (SAQD). in a ~0.6 mm-thick near-surface layer were investigated. Analysis of photo- and electrophysical performances allowed to revel ~10—103 Iph(V) photocurrent gain by p-n-junction at T = 78 K upon photodiode radiation with the photon energy corresponding to Si and Ge basic interband transitions. A model is proposed which assumes that SAQDs with a positive charge at T = 78 K turn out to by trapping centers for electrons/At “forward” voltages on a photodiode (V > 0.2), when the p-layer SAQDs are already partially outside the p-n-junction, there takes place electron capture on SAQDs as on adhesion centers under conditions of photocarrier optical generation in Si. In this case, excess concentration of the p-layer electrons forming oxsiton-type bound stares with quantum dots leads to lowering the p-n-junction potential barrier and photocurrent amplification.
